JP3933084B2

JP3933084B2 - Spreading code allocation method and base station in code division multiplexing cellular

Info

Publication number: JP3933084B2
Application number: JP2003107713A
Authority: JP
Inventors: 浩古川; 彰久後川
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2003-04-11
Filing date: 2003-04-11
Publication date: 2007-06-20
Anticipated expiration: 2019-11-01
Also published as: JP2003333669A

Description

【０００１】
【発明の属する技術分野】
本発明は、基地局から複数の移動局へ向けた送信信号が拡散符号によって拡散され伝送される符号分割多重セルラにおける拡散符号割り当て方法及び基地局に関する。
【０００２】
【従来の技術】
符号分割多重セルラの下り回線では、基地局において複数の移動局へ向けた送信信号がそれぞれ異なる拡散符号によって拡散、重畳された後に一括して送信される。下り回線では、複数の移動局へ向けた信号が基地局から一括して伝送されるため、送信信号間の同期を取ることが容易である。そこで、各送信信号を直交同期符号により拡散することによって送信信号間の干渉を抑制することが可能となる。
【０００３】
一方、他基地局からの下り回線信号は同期を取ることが困難であるため、これらの基地局からの干渉を抑制する手段として、直交同期符号にさらに基地局固有のスクランブル符号を乗じる手法が用いられる。ここで、スクランブル符号としてはゴールド符号等が用いられる。
【０００４】
本手法を用いた場合の基地局送信装置構成を図１２に示す。図１２に示す拡散加算装置ｓｐｕでは、乗算器００１において移動局へ向けた送信信号Ｓｉ（ｉは移動局番号）と直交符号Ｃｏ，ｉとが掛け合わされ、掛け合わせた後の出力信号は加算器００２において加算され、さらに加算器００２の出力信号は乗算器００１においてスクランブル符号Ｃｓと掛け合わされて合成拡散信号ｓｄが出力される。合成拡散信号ｓｄは、変調装置００３において変調がかけられた後にアンテナ００４から各移動局へ向けて送信される。
【０００５】
上述の図１２に示した拡散手法を全ての基地局が用いることによって、移動局において受信される他基地局からの下り回線干渉はランダム化され、誤り訂正符号との併用によってこれらの干渉を抑制することができる。
【０００６】
【発明が解決しようとする課題】
ＣＤＭＡセルラシステムでは以下のような理由により符号消費が促進されるため、直交符号に不足が生じる状況が多く発生する。
【０００７】
まず、ソフトハンドオーバ（ＳｏｆｔＨａｎｄ−Ｏｖｅｒ；ＳＨＯ）が適用されると複数の基地局が１移動局のために同一信号を送信するために、ＳＨＯが適用されない場合に比べて符号消費が増す。また、音声の無音区間では信号の送信を一時停止して干渉を減らし、より多くの移動局を収容する方法が取られるために、常にオン状態である情報源を伝送する場合に比べて符号消費が増える。さらに、符号消費は伝搬環境によっても変化し、伝搬路に遮蔽物が多く存在する場合等は他セル干渉がよく抑圧されて容量が増すために、基地局での符号消費が増える。
【０００８】
以上のような理由により基地局に直交符号数を超える数の移動局が接続される場合には、１基地局で複数のスクランブル符号を用いることで拡散符号不足に対処する手法が取られる。
【０００９】
図１３はｋ個のスクランブル符号を用いる場合の基地局送信装置構成を示した図である。拡散加算装置ｓｐｕ−ｊ（ｊはスクランブル符号番号）では、送信信号Ｓｊ，ｈ（ｈは直交符号番号）、直交符号Ｃｏ，ｈ、およびスクランブル符号Ｃｓ，ｊがそれぞれ入力され、合成拡散信号ｓｄ−ｊが出力される。図１３中のｎｊはｊ番目スクランブル符号より生成される直交符号の使用数を表している。合成拡散信号の出力ｓｄ−ｊは加算器００２において加算された後、変調装置００３で変調がかけられてアンテナ００４より各移動局へ向けて放出される。
【００１０】
図１３のように１基地局で複数のスクランブル符号を同時に用いる場合、伝送速度、所要ビット誤り率などの要求品質が異なる送信信号や、セル内での移動局位置、干渉量等に依存する受信品質の異なる送信信号が１つの基地局において取り扱われると、割り当てられたスクランブル符号の違いのために各送信信号が受ける同一セル内の他の送信信号からの干渉の程度に差が生じ、通信品質の不平等や干渉劣化が生じる問題があった。
【００１１】
【課題を解決するための手段】
スクランブル符号と直交符号とを乗じることで生成される拡散符号に優先度を設け、前記優先度を移動局の要求品質や受信品質によって変化させる。
【００１２】
拡散符号の優先度を要求品質や受信品質によって変化させることで、異なる要求品質、受信品質をもった移動局間の干渉を制御し、移動局における信号受信品質の不公平を緩和し、不公平によって生じる干渉劣化を抑制する。
【００１３】
【発明の実施の形態】
［構成の説明］
本発明の第一の実施形態における拡散符号割当方法では、複数の第一符号を含む第一の符号セットと、１又は複数の第二符号を含む第二の符号セットとを有している。ここで、第一符号は、直交符号が該当し、第二符号はスクランブル符号が該当する。スクランブル符号としては、ゴールド符号やゴールド符号の一部等を用いることができる。
【００１４】
そして、第一の符号セットに第二符号を割り当て、複数の第一の符号に前記割り当てた第二符号を乗じて複数の結合符号を生成する。結合符号が生成されると、基地局から移動局に送信される送信信号に結合符号を割り当て、割り当てられた結合符号により送信信号を拡散し、拡散された送信信号を移動局へ送信する。
【００１５】
本発明では、結合符号に優先度を付ける。そして、優先度の高い結合符号から優先して送信信号に割り当てる。ここで、優先度は送信信号毎に変化させる。具体的には、移動局からの回線品質値情報や要求品質値情報に基づいて優先度を送信信号毎に変化させる。
【００１６】
以下では、本発明の拡散符号割当方法を基地局送信装置に適用した第一の実施の形態を図１及び図２を用いて説明する。
【００１７】
図１はｋ個のスクランブル符号を用いる場合の基地局送信装置構成を示した図である。
【００１８】
本発明の第一の実施の形態は、拡散加算装置ｓｐｕ−ｊ（ｊはスクランブル符号番号）と、加算器００２と、変調装置００３と、アンテナ００４とから構成される。
【００１９】
拡散加算装置ｓｐｕ−ｊは、送信信号Ｓｊ，ｈ（ｈは直交符号番号）に対して、直交符号Ｃｏ，ｈ、およびスクランブル符号Ｃｓ，ｊの結合符号を割り当て、合成拡散信号ｓｄ−ｊを出力する。図１中のｎｊはｊ番目スクランブル符号より生成される直交符号の使用数を表している。ここで、送信信号には共通制御信号が含まれてもよい。
【００２０】
加算器００２は、合成拡散信号の出力ｓｄ−ｊのおのおのを加算する。
【００２１】
変調装置００３は、加算器００２で加算されたで合成拡散信号を変調する。
【００２２】
アンテナ００４は、変調装置００３で変調された合成拡散信号を各移動局へ向けて放出する。
【００２３】
フィードバック情報受信手段００５は、アンテナ００６より移動局からフィードバック情報として回線品質情報や要求品質情報を受信する。
【００２４】
優先度決定手段００７は、フィードバック情報受信手段００５からフィードバック情報を受け取り、この情報に基づいて送信信号毎に結合符号の優先度を決定する。
【００２５】
［動作の説明］
次に本実施の形態の動作について図１及び図２を用いて説明する。
【００２６】
図２は、直交符号とスクランブル符号から構成される結合符号を移動局へ割り当てる際に、基地局における割り当て処理の流れ図を示している。
【００２７】
基地局は、処理１０１において、変数ｍａに符号割り当ての対象となる移動局の番号を設定する。処理１０２において、移動局ｍａからフィードバック情報の伝達を受ける。ここでフィードバック情報として、共通制御信号の受信電力、希望信号対干渉信号電力比等の回線品質値情報や、伝送速度、所要誤り率等の要求品質値情報を与える。
【００２８】
ここで、回線品質値として希望信号電力対干渉信号電力比を採用した場合、接続中の基地局より放出された共通制御信号の受信電力を調べ、非接続中の基地局より放出された共通制御信号の受信電力を調べ、接続中の基地局に対応する受信電力と非接続中の基地局に対応する受信電力との比により希望信号対干渉信号電力比を算出することができる。
【００２９】
処理１０３においてフィードバック情報に基づいて結合符号の優先度を設定し、さらに処理１０４において優先度変数ｐに１、すなわち最上位優先度を設定する。処理１０６において、優先度ｐの結合符号が使用中であるか否かを判定し、優先度ｐの結合符号が使用中であれば、処理１０５において優先度変数ｐに１を加えて処理１０６へ戻る。
【００３０】
処理１０６において優先度ｐの結合符号が使用中でないと判断された場合には、処理１０７において優先度ｐの結合符号を移動局ｍａに割り当て、割り当てた結合符号情報を基地局から移動局ｍａに通知し、符号割り当て処理を完了する。
【００３１】
なお、割り当てられた符号を用いて基地局から移動局へ送信する送信信号には共通制御信号を含めることができ、この場合、共通制御信号には最も優先度の高い結合符号を割り当てるのが良い。
【００３２】
［第一の優先度の設定例］
図３、図４ならびに図５は、本発明の第一の実施の形態である図２の処理１０３において優先度決定手段００７にて設定される各結合符号の優先度の設定例を示している。この例では、回線品質値に基づいて優先度を設定する。
【００３３】
図３の横軸は移動局が観測する回線品質値を表し、図３のように回線品質値はいくつかのしきい値で分割される。回線品質値としては、移動局で観測される干渉電力、移動局が受信する共通制御信号受信電力、および希望信号電力対干渉信号電力比等が考えられる。移動局が測定したこれらの回線品質値は図２の処理１０２において基地局へ伝達される。
【００３４】
図３に示すように、前記しきい値で区切られた複数の値域にはそれぞれ回線品質値分類を設定する。これにより同程度の回線品質値に対しては等しい回線品質値分類が適用される。移動局で観測された回線品質値に応じて、図３より回線品質値分類が選択される。
【００３５】
基地局では、優先度決定手段００７にて回線品質分値に基づいて、具体的には回線品質値分類毎に、結合符号の優先度を決定する。その際に第二符号であるスクランブル符号にに優先度を付け、又は直交符号である第一符号及び第二符号に優先度を付けて、結合符号の優先度を決定する。その際に回線品質値分類毎にスクランブル符号の優先度又はスクランブル符号及び直交符号の優先度を等しく設定する。
【００３６】
図４及び図５は、回線品質値分類Ｑ１、Ｑ２における各結合符号の優先度の設定例を示したものである。図４（ａ）,（ｂ）、図５（ａ），（ｂ）に示した各表における横軸はスクランブル符号の番号を、縦軸は直交符号の番号を表し、表の各要素が各結合符号の優先度である。
【００３７】
図４の例では、スクランブル符号に優先度を設け回線品質値に応じてスクランブル符号の優先度を変化さている。図４（ａ）では、スクランブル符号１の優先度が１、スクランブル符号２の優先度が２とされ、図４（ｂ）のスクランブル符号１の優先度が２、スクランブル符号２の優先度が１と設定されている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００３８】
その結果、図４（ａ）のスクランブル符号１で構成される結合符号群に優先度を１〜８を割り当て、図４（ａ）スクランブル符号２で構成される結合符号群に優先度９〜１６が割り当てられ、図４（ｂ）のスクランブル符号１で構成される結合符号群に優先度９〜１６が割り当てられ、図４（ｂ）のスクランブル符号２で構成される結合符号群に優先度１〜８が割り当てられている。この例では直交符号には優先度は付けられておらず、スクランブル符号毎に、直交符号がランダムに割当られている。
【００３９】
図５の例では、図４の例と同様にスクランブル符号に優先度を設け回線品質値に応じてスクランブル符号の優先度を変化させている。図５（ａ）では、スクランブル符号１の優先度が１、スクランブル符号２の優先度が２とされ、図５（ｂ）のスクランブル符号１の優先度が２、スクランブル符号２の優先度が１と設定されている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００４０】
その結果、図５（ａ）のスクランブル符号１で構成される結合符号群に優先度を１〜８を割り当て、図５（ａ）スクランブル符号２で構成される結合符号群に優先度９〜１６が割り当てられ、図５（ｂ）のスクランブル符号１で構成される結合符号群に優先度９〜１６が割り当てられ、図５（ｂ）のスクランブル符号２で構成される結合符号群に優先度１〜８が割り当てられている。
【００４１】
更に、この例では、直交符号符号に優先度を設けている。具体的には、図５（ａ）,（ｂ）では、直交符号１、２、…、８にそれぞれ直交符号の優先度を１、２…８としている。そして、これら直交符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００４２】
具体的には、図５（ａ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１）（１，２）…（１，８）；（スクランブル符号番号，直交符号番号）、に対して１、２、…、８としている。また、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１）（２，２）…（２，８）、に対して９、１０、…、１６としている。また図５（ｂ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１）（１，２）…（１，８）に対して９、１０、…、１６としている。また、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１）（２，２）…（２，８）、に対して１、２、…、８としている。
【００４３】
なお、この図５（ａ）,（ｂ）の例では、一律に直交符号の優先度を定めているが、スクランブル符号と同様に回線品質値に応じて優先度を変化させても良い。
【００４４】
［効果］
下り回線の送信電力制御が適用される場合、各移動局へ向けた送信電力は回線品質によって変化し、送信電力の相異は各移動局が受信する他の下り送信信号からの干渉量に不平等を引き起こす。図４、５のように、本実施の形態によると回線品質値分類によって結合符号の優先度が変わり、送信信号と結合符号の割り当てが回線品質で分類分けされる。これによって、回線品質の相違に起因する各移動局における通話受信品質の不平等が抑制される。
【００４５】
特に回線品質値として共通制御信号受信電力が用いられている場合には以下に述べるような干渉低減効果が期待できる。
【００４６】
図３、図４、図５に示した本実施の形態によると共通制御信号受信電力が同程度の移動局、すなわち基地局と移動局との伝播損失が同程度である移動局へは等しいスクランブル符号が割り当てられる。同一のスクランブル符号が割り当てられた送信信号間は同一の直交符号セットが割り当てられるために相互の干渉が小さく抑えられる。
【００４７】
送信電力制御が行われる場合、共通制御信号受信電力が低い移動局へ向けた送信信号、すなわち基地局までの伝播損失が大きい移動局へ向けた送信信号は、基地局から大きな出力でもって放出され、これが他の無線回線へ大きな干渉をおよぼす。図３、図４、図５に示した本実施の形態によると、当該送信信号には同一の直交符号セットからなる結合符号が割り当てるために、当該送信信号間の相互の干渉が抑制される。
【００４８】
一方、共通制御信号受信電力が高い移動局へ向けた送信信号、すなわち基地局までの伝播損失が小さい移動局へ向けた送信信号へは、伝播損を補償するための送信電力は小さく設定できる。このように送信電力の設定に余裕がある送信信号では、前記共通制御信号受信電力が小さい移動局へ向けた送信信号から大きな干渉を受けても、干渉に打ち勝つだけの高い送信電力を設定することが可能となり、干渉の軽減が期待できる。
【００４９】
［第二の優先度の設定例］
図６は、本発明の第一の実施の形態である図１の処理１０２において基地局の優先度決定手段００７にて設定される各結合符号の優先度の第二の設定例を示している。この例では、伝送品質要求量に基づいて優先度を設定する。伝送品質要求量としては伝送速度、伝送誤り率や、伝送速度と伝送誤り率の関数等が考えられる。
【００５０】
図６の横軸および縦軸は、それぞれ、移動局が要求する伝送速度および伝送誤り率を表している。図６のｌ−１，ｌ−２，ｌ−３，ｌ−４は、伝送品質要求量分類Ｑｏ−ａ，〜Ｑｏ−ｉを規定するための境界線である。移動局が要求したこれらの伝送品質要求量は図２の処理１０２において基地局へ伝達される。図６では、同程度の伝送速度、伝送誤り率に対しては等しい伝送品質要求量分類が適用されるようにしている。
【００５１】
移動局で要求された伝送品質要求量に基づき、送信信号の伝送速度ならびに当該送信信号に必要とされる伝送誤り率に応じて、図６における伝送品質要求量分類が選択される。
【００５２】
基地局では、優先度決定手段００７にて伝送品質要求量に基づいて、具体的には伝送品質要求量分類毎に、結合符号の優先度を決定する。その際に第二符号であるスクランブル符号にに優先度を付け、又は直交符号である第一符号及び第二符号に優先度を付けて、結合符号の優先度を決定する。その際に伝送品質要求量分類毎にスクランブル符号の優先度又はスクランブル符号及び直交符号の優先度を等しく設定する。
【００５３】
図７及び図８は伝送品質要求量分類Ｑｏ−ａ，Ｑｏ−ｂにおける各結合符号の優先度の設定例を示したものである。図７（ａ），（ｂ）、図８（ａ），（ｂ）に示した各表における横軸はスクランブル符号の番号を、縦軸は直交符号の番号を表し、表の各要素が各結合符号の優先度である。
【００５４】
伝送品質要求量分類Ｑｏ−ｂでは、Ｑｏ−ａよりも高速な伝送を想定しており、１通話当たりの符号占有量をＱｏ−ａよりも大きく設定している。このような高速伝送を実現するための符号生成手法として、複数の直交符号を同時に用いる手法や、階層型直交符号を用いる手法が知られている。
【００５５】
図７の例では、スクランブル符号に優先度を設け伝送品質要求量に応じてスクランブル符号の優先度を変化させている。図７（ａ）では、スクランブル符号１の優先度が１、スクランブル符号２の優先度が２とされ、図７（ｂ）のスクランブル符号１の優先度が２、スクランブル符号２の優先度が１と設定されている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００５６】
その結果、図７（ａ）のスクランブル符号１で構成される結合符号群に優先度１〜８が割り当てられ、図７（ａ）のスクランブル符号２で構成される結合符号群に優先度９〜１６が割り当てられ、図７（ｂ）のスクランブル符号１で構成される結合符号群の優先度５〜８が割り当てられ、図７（ｂ）のスクランブル符号２で構成される結合符号群に優先度１〜４が割り当てられている。この例では直交符号には優先度は付けられておらず、スクランブル符号毎に、直交符号がランダムに割当られている。
【００５７】
図８の例では、図７の例と同様にスクランブル符号に優先度を設け伝送品質要求量に応じてスクランブル符号の優先度を変化させている。図８（ａ）では、スクランブル符号１の優先度が１、スクランブル符号２の優先度が２とされ、図８（ｂ）のスクランブル符号１の優先度が２、スクランブル符号２の優先度が１と設定されている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００５８】
その結果、図８（ａ）のスクランブル符号１で構成される結合符号群に優先度１〜８が割り当てられ、図８（ａ）のスクランブル符号２で構成される結合符号群に優先度９〜１６が割り当てられ、図８（ｂ）のスクランブル符号１で構成される結合符号群の優先度５〜８が割り当てられ、図８（ｂ）のスクランブル符号２で構成される結合符号群に優先度１〜４が割り当てられている。
【００５９】
更に、この例では、直交符号に優先度を設けている。具体的には、図８（ａ）では、直交符号１、２、…、８にそれぞれ直交符号の優先度を１、２…８としている。図８（ｂ）では、直交符号１及び２、３及び４、５及び６、７及び８にそれぞれ直交符号の優先度を１、２、３、４としている。
【００６０】
そして、これら直交符号の優先度が高いほど結合符号の優先度が高く設定されている。具体的には、図８（ａ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１）（１，２）…（１，８）；（スクランブル符号番号，直交符号番号）、に対して１、２、…、８としている。また、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１）（２，２）…（２，８）、に対して９、１０、…、１６としている。
【００６１】
また図８（ｂ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１＆２）、（１，３＆４）、（１，５＆６）、（１，７＆８）に対して５、６、７、８としている。また、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１＆２）、（２，３＆４）、（２，５＆６）、（２，７＆８）、に対して１、２、３、４としている。
【００６２】
ここで、結合符号（Ａ，Ｂ＆Ｃ）は、スクランブル符号Ａに対して、ＢとＣの直交符号を同時に用いていることを示す。
【００６３】
［効果］
図６、７、８のように、本実施形態では伝送品質要求量分類によって結合符号の優先度を変えている。このように、伝送速度や伝送誤り率等で与えられる伝送品質要求量に応じて結合符号の優先度を変えることで、送信信号と結合符号の割り当てが伝送速度や伝送誤り率によって分類分けされる。
【００６４】
一般に高速伝送の送信信号程、もしくは低い誤り率を要求する送信信号程、必要な送信電力は大きなものとなる。他信号へ大きな干渉を与えうるこれらの送信信号に等しいスクランブル符号を割り当てることで、当該送信信号間の干渉を抑えることができる。
【００６５】
一方、低速伝送もしくは高い誤り率が許容できる送信信号は、異なるスクランブル符号が割り当てられた高速伝送もしくは低い誤り率を要求する送信信号から大きな干渉を受けるが、低速伝送もしくは高い誤り率が許容できる送信信号は必要とする送信電力が低いため、送信電力制御の適用によって、大きな干渉に打ち勝つことができる。また、伝送速度や誤り率に応じてスクランブル符号を割り当てることで、受信通話品質の不平等を抑制することもできる。
【００６６】
［第三の優先度の設定例］
図９、図１０、図１１は、本発明の第一の実施の形態である図１の処理１０２において基地局の優先度決定手段００７にて設定される各結合符号の優先度の第三の設定例を示している。本設定例においては、回線品質値と第二符号の使用数に基づいて優先度を設定する。
【００６７】
まず、基地局は事前に結合符号の使用数を各スクランブル符号毎に調べる。図９はその一例を示したものであり、横軸はスクランブル符号の番号、縦軸は各スクランブル符号の使用数を表している。図９では、第二スクランブル符号がもっとも使用数が高く、第四スクランブル符号がもっとも使用数が低い様子を想定している。
【００６８】
基地局は、当該スクランブル符号使用数ならびに移動局より伝達された回線品質値により結合符号の優先度を決定する。ここで、回線品質値として、移動局で観測される干渉電力、移動局における共通制御信号受信電力や、希望信号対干渉信号電力比を与え、回線品質値情報は図１の処理１０８において移動局から基地局へ伝達される。
【００６９】
図１０、１１は、図９で与えられるスクランブル符号使用数の下での各結合符号の優先度の設定例を示したものである。各表の縦軸は直交符号番号を表し、横軸はスクランブル符号番号を表している。
【００７０】
図１０の例では、移動局より伝達された前記回線品質値が品質しきい値以上である場合には、図１０（ａ）に示すように、当該スクランブル符号使用数の下で使用数が最も少ないスクランブル符号ほど優先度を高く設定する。
【００７１】
具体的には、スクランブル符号４の優先度を１、スクランブル符号３の優先度を２、スクランブル符号１の優先度を３、スクランブル符号２の優先度を４としている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。その結果、図１０（ａ）のスクランブル符号１で構成される結合符号群に優先度１７〜２４が、スクランブル符号２で構成される結合符号群に優先度２５〜３２が、スクランブル符号３で構成される結合符号群に優先度９〜１６、スクランブル符号４で構成される結合符号群に優先度１〜８が割り当てられている。
【００７２】
一方、移動局より伝達された前記回線品質値が品質しきい値未満である場合には、図１０（ｂ）に示すように、当該スクランブル符号使用数の下で使用数が多いスクランブル符号ほど優先度を高く設定する。
【００７３】
具体的には、スクランブル符号２の優先度を１、スクランブル符号１の優先度を２、スクランブル符号３の優先度を３、スクランブル符号４の優先度を４としている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。その結果、図１０（ｂ）のスクランブル符号１で構成される結合符号群に優先度９〜１６が、スクランブル符号２で構成される結合符号群に優先度１〜８が、スクランブル符号３で構成される結合符号群に優先度１７〜２４が、スクランブル符号４で構成される結合符号群に優先度２５〜３２が割り当てられている。
【００７４】
この例では直交符号には優先度は付けられておらず、スクランブル符号毎に、直交符号がランダムに割当られている。
【００７５】
また、図１１の例では、図１０の例と同様に、移動局より伝達された前記回線品質値が品質しきい値以上である場合には、図１１（ａ）に示すように、当該スクランブル符号使用数の下で使用数が最も少ないスクランブル符号ほど優先度を高く設定する。
【００７６】
具体的には、スクランブル符号４の優先度を１、スクランブル符号３の優先度を２、スクランブル符号１の優先度を３、スクランブル符号２の優先度を４としている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。その結果、図１１（ａ）のスクランブル符号１で構成される結合符号群に優先度１７〜２４が、スクランブル符号２で構成される結合符号群に優先度２５〜３２が、スクランブル符号３で構成される結合符号群に優先度９〜１６、スクランブル符号４で構成される結合符号群に優先度１〜８が割り当てられている。
【００７７】
一方、移動局より伝達された前記回線品質値が品質しきい値未満である場合には、図１１（ｂ）に示すように、当該スクランブル符号使用数の下で使用数が多いスクランブル符号ほど優先度を高く設定する。
【００７８】
具体的には、スクランブル符号２の優先度を１、スクランブル符号１の優先度を２、スクランブル符号３の優先度を３、スクランブル符号４の優先度を４としている。そして、これらスクランブル符号の優先度が高いほど結合符号の優先度が高く設定されている。その結果、図１１（ｂ）のスクランブル符号１で構成される結合符号群に優先度９〜１６が、スクランブル符号２で構成される結合符号群に優先度１〜８が、スクランブル符号３で構成される結合符号群に優先度１７〜２４が、スクランブル符号４で構成される結合符号群に優先度２５〜３２が割り当てられている。
【００７９】
図１１の例では、更に直交符号についても優先度が付けられている。具体的には、直交符号１、２、…、８にそれぞれ直交符号の優先度を１、２…８としている。そして、これら直交符号の優先度が高いほど結合符号の優先度が高く設定されている。
【００８０】
具体的には、図１１（ａ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１）（１，２）…（１，８）；（スクランブル符号番号，直交符号番号）、に対して１７、１８、…、２４とし、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１）（２，２）…（２，８）、に対して２５、２６、…、３２とし、スクランブル符号３で構成される結合符号群の優先度を結合符号（３，１）（３，２）…（３，８）、に対して９、１０、…、１６とし、スクランブル符号４で構成される結合符号群の優先度を結合符号（４，１）（４，２）…（４，８）、に対して１、２、…、８としている。
【００８１】
また図１１（ｂ）のスクランブル符号１で構成される結合符号群の優先度を結合符号（１，１）（１，２）…（１，８）に対して９、１０、…、１６とし、スクランブル符号２で構成される結合符号群の優先度を結合符号（２，１）（２，２）…（２，８）、に対して１、２、…、８とし、スクランブル符号３で構成される結合符号群の優先度を結合符号（３，１）（３，２）…（３，８）、に対して１７、１８、…、２４とし、スクランブル符号４で構成される結合符号群の優先度を結合符号（４，１）（４，２）…（４，８）、に対して２５、２６、…、３２としている。
【００８２】
なお、この図１１（ａ）,（ｂ）の例では、一律に直交符号の優先度を定めているが、スクランブル符号と同様に結合符号の使用数に応じて直交符号の優先度を変化させても良い。
【００８３】
［効果］
異なるスクランブル符号が割り当てられた信号間は、符号の直交性が保たれないために相互の干渉量が大きい。とくに、使用数が少ないスクランブル符号が割り当てられた送信信号は、使用数が多いスクランブル符号が割り当てられた送信信号から大きな干渉を受ける。
【００８４】
送信電力制御が適用される場合、回線品質値が品質しきい値である場合、すなわち移動局における受信品質が良好である場合には、当該移動局へ向けた送信電力は低く設定できる。この場合、図９、図１０、図１１のように、回線品質値が高い移動局へ使用数が少ないスクランブル符号で構成される結合符号を割り当てても、当該移動局へ向けた送信信号は最大送信電力に達することなく干渉に耐えることができる。これによって干渉劣化の抑制が可能となる。
【００８５】
なお、以上本発明の拡散符号割当方法を基地局装置に適用した例を用いて説明したが、基地局装置ではなく制御局や交換局において実現することも当然にできる。
【００８６】
【発明の効果】
拡散符号の優先度を移動局における要求品質や受信品質によって変化させることで、移動局における通話受信品質の不平等が抑制され、干渉が低減される。
【図面の簡単な説明】
【図１】本発明の拡散符号割当方法を適用した基地局装置のブロック図
【図２】本発明の第一の実施形態を示す符号割り当て処理の流れ図
【図３】本発明の第一の実施形態における結合符号割り当ての第一の優先度の設定例における回線品質値と回線品質値分類の関係の一例を示す図
【図４】本発明の第一の実施形態における結合符号割り当ての第一の優先度の設定例を示す図
【図５】本発明の第一の実施形態における結合符号割り当ての第一の優先度の設定例を示す図
【図６】本発明の第一の実施形態における結合符号割り当ての第二の優先度の設定例における伝送速度と伝送誤り率に対する伝送品質要求量分類の一例を示す図
【図７】本発明の第一の実施形態における結合符号割り当ての第二の優先度の設定例を示す図
【図８】本発明の第一の実施形態における結合符号割り当ての第二の優先度の設定例を示す図
【図９】本発明の第一の実施形態における結合符号割り当ての第三の優先度の設定例におけるスクランブル符号使用数を示す図
【図１０】本発明の第一の実施形態における符号組割り当ての第三の優先度の設定例を示す図。
【図１１】本発明の第一の実施形態における符号組割り当ての第三の優先度の設定例を示す図。
【図１２】従来の単数スクランブル符号拡散による基地局送信装置
【図１３】従来の複数スクランブル符号拡散による基地局送信装置
【符号の説明】
００２：乗算器
００３：変調装置
００４：アンテナ
００５：フィードバック情報受信手段
００６：アンテナ
００７：優先度決定手段
Ｓｉ：移動局ｉへ向けた送信信号
Ｃｏ，ｉ：移動局ｉに割り当てる直交符号
ｓｐｕ：拡散加算装置
ｓｄ：合成拡散信号
Ｃｓ：スクランブル符号
Ｓｊ，ｈ：スクランブル符号ｊが割り当てられた移動局ｈの送信信号
ｋ：ある基地局で消費するスクランブル符号数
Ｃｓ，ｊ：ｊ番目のスクランブル符号
ｓｐｕ−ｊ：スクランブル符号ｊで拡散する拡散加算装置
ｓｄ−ｊ：スクランブル符号ｊに対する合成拡散信号
ｎｊ：スクランブル符号ｊを使用する移動局数
Ｓ：直交符号数
ｌ−１，ｌ−２，ｌ−３，ｌ−４：伝送品質要求量分類を規定する境界線
Ｑｏ−ａ〜Ｑｏ−ｉ：伝送品質要求量分類
Ｑ１，Ｑ２，Ｑ３：回線品質値分類[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spreading code assigning method and a base station in a code division multiplexing cellular where transmission signals from a base station to a plurality of mobile stations are spread and transmitted by spreading codes.
[0002]
[Prior art]
In a code division multiplexing cellular downlink, transmission signals for a plurality of mobile stations are spread and superposed by different spreading codes at a base station, and then transmitted together. In the downlink, since signals directed to a plurality of mobile stations are collectively transmitted from the base station, synchronization between transmission signals is easy. Therefore, it is possible to suppress interference between transmission signals by spreading each transmission signal with an orthogonal synchronization code.
[0003]
On the other hand, since it is difficult to synchronize downlink signals from other base stations, a method of multiplying the orthogonal synchronization code by a scramble code unique to the base station is used as a means for suppressing interference from these base stations. It is done. Here, a gold code or the like is used as the scramble code.
[0004]
FIG. 12 shows the configuration of a base station transmission apparatus when this method is used. In the spread adder spu shown in FIG. 12, a multiplier 001 multiplies a transmission signal Si (i is a mobile station number) directed to a mobile station and an orthogonal code Co, i, and the output signal after the multiplication is an adder. The signal is added at 002, and the output signal of the adder 002 is multiplied by a scramble code Cs at a multiplier 001 to output a combined spread signal sd. The combined spread signal sd is modulated by the modulation device 003 and then transmitted from the antenna 004 to each mobile station.
[0005]
When all the base stations use the spreading method shown in FIG. 12 described above, downlink interference from other base stations received by the mobile station is randomized, and these interferences are suppressed by using the error correction code together. can do.
[0006]
[Problems to be solved by the invention]
In the CDMA cellular system, code consumption is promoted for the following reasons, so that there are many situations in which the orthogonal code is deficient.
[0007]
First, when soft handover (Soft Hand-Over; SHO) is applied, a plurality of base stations transmit the same signal for one mobile station, so that the code consumption increases as compared with the case where SHO is not applied. Also, in the silent section of speech, the transmission of signals is temporarily stopped to reduce interference, and a method of accommodating more mobile stations is adopted, so that the code consumption is compared with the case of transmitting information sources that are always on. Will increase. Furthermore, code consumption also changes depending on the propagation environment, and when there are many shields in the propagation path, interference from other cells is well suppressed and the capacity increases, so that code consumption at the base station increases.
[0008]
When the number of mobile stations exceeding the number of orthogonal codes is connected to the base station for the reasons as described above, a technique for dealing with the shortage of spreading codes is used by using a plurality of scramble codes in one base station.
[0009]
FIG. 13 is a diagram showing a configuration of a base station transmission apparatus when k scrambling codes are used. In the spread adder spu-j (j is a scramble code number), transmission signals Sj, h (h is an orthogonal code number), orthogonal code Co, h, and scramble code Cs, j are respectively input, and a combined spread signal sd- j is output. In FIG. 13, nj represents the number of orthogonal codes generated from the jth scramble code. The output sd-j of the combined spread signal is added by the adder 002, modulated by the modulator 003, and emitted from the antenna 004 toward each mobile station.
[0010]
When a plurality of scramble codes are used simultaneously in one base station as shown in FIG. 13, reception depends on transmission signals having different required qualities such as transmission rate and required bit error rate, mobile station position in the cell, interference amount, etc. When transmission signals with different qualities are handled in one base station, a difference occurs in the degree of interference from other transmission signals in the same cell received by each transmission signal due to the difference in the assigned scramble codes. Inequality and interference degradation occurred.
[0011]
[Means for Solving the Problems]
A priority is provided to a spread code generated by multiplying a scramble code and an orthogonal code, and the priority is changed according to the required quality and reception quality of the mobile station.
[0012]
By changing the priority of spreading codes according to required quality and reception quality, interference between mobile stations with different required quality and reception quality is controlled, and unfairness in signal reception quality at the mobile station is alleviated and unfair. Suppresses the interference degradation caused by
[0013]
DETAILED DESCRIPTION OF THE INVENTION
[Description of configuration]
The spreading code assignment method according to the first embodiment of the present invention includes a first code set including a plurality of first codes and a second code set including one or more second codes. Here, the first code corresponds to an orthogonal code, and the second code corresponds to a scramble code. As the scramble code, a gold code, a part of the gold code, or the like can be used.
[0014]
Then, a second code is assigned to the first code set, and a plurality of combined codes are generated by multiplying the plurality of first codes by the assigned second code. When the joint code is generated, the joint code is assigned to the transmission signal transmitted from the base station to the mobile station, the transmission signal is spread by the assigned joint code, and the spread transmission signal is transmitted to the mobile station.
[0015]
In the present invention, priority is given to the combined code. And it assigns to a transmission signal with priority from the combination code with high priority. Here, the priority is changed for each transmission signal. Specifically, the priority is changed for each transmission signal based on channel quality value information and required quality value information from the mobile station.
[0016]
In the following, a first embodiment in which the spreading code allocation method of the present invention is applied to a base station transmission apparatus will be described with reference to FIGS.
[0017]
FIG. 1 is a diagram showing a configuration of a base station transmission apparatus when k scrambling codes are used.
[0018]
The first embodiment of the present invention includes a spread adder spu-j (j is a scramble code number), an adder 002, a modulator 003, and an antenna 004.
[0019]
The spread adder spu-j assigns a combined code of the orthogonal code Co, h and the scramble code Cs, j to the transmission signal Sj, h (h is an orthogonal code number), and outputs a combined spread signal sd-j To do. In FIG. 1, nj represents the number of orthogonal codes generated from the jth scramble code. Here, the transmission signal may include a common control signal.
[0020]
The adder 002 adds each of the outputs sd-j of the combined spread signal.
[0021]
The modulation device 003 modulates the combined spread signal after being added by the adder 002.
[0022]
The antenna 004 emits the combined spread signal modulated by the modulation device 003 toward each mobile station.
[0023]
Feedback information receiving means 005 receives channel quality information and required quality information from the mobile station as feedback information from antenna 006.
[0024]
The priority determining unit 007 receives feedback information from the feedback information receiving unit 005, and determines the priority of the combined code for each transmission signal based on this information.
[0025]
[Description of operation]
Next, the operation of this embodiment will be described with reference to FIGS.
[0026]
FIG. 2 shows a flowchart of an allocation process in the base station when a combined code composed of an orthogonal code and a scramble code is allocated to a mobile station.
[0027]
In step 101, the base station sets the number of the mobile station that is the target of code assignment in the variable ma. In process 102, feedback information is received from the mobile station ma. Here, as the feedback information, the line quality value information such as the received power of the common control signal, the desired signal-to-interference signal power ratio, and the required quality value information such as the transmission rate and the required error rate are given.
[0028]
Here, when the desired signal power to interference signal power ratio is adopted as the channel quality value, the reception power of the common control signal emitted from the connected base station is checked, and the common control emitted from the non-connected base station is checked. The received signal power is examined, and the desired signal to interference signal power ratio can be calculated from the ratio of the received power corresponding to the connected base station and the received power corresponding to the disconnected base station.
[0029]
In process 103, the priority of the combined code is set based on the feedback information, and in process 104, the priority variable p is set to 1, that is, the highest priority. In process 106, it is determined whether or not a combination code with priority p is in use. If a combination code with priority p is in use, 1 is added to priority variable p in process 105 and the process proceeds to process 106. Return.
[0030]
If it is determined in process 106 that the combined code of priority p is not in use, the combined code of priority p is assigned to the mobile station ma in process 107, and the assigned combined code information is transferred from the base station to the mobile station ma. Notify and complete the code allocation process.
[0031]
Note that a transmission signal transmitted from the base station to the mobile station using the assigned code can include a common control signal. In this case, it is preferable to assign a joint code having the highest priority to the common control signal. .
[0032]
[Example of setting the first priority]
3, 4 and 5 show setting examples of the priority of each combined code set by the priority determination means 007 in the process 103 of FIG. 2 which is the first embodiment of the present invention. . In this example, the priority is set based on the line quality value.
[0033]
The horizontal axis in FIG. 3 represents the channel quality value observed by the mobile station, and the channel quality value is divided into several threshold values as shown in FIG. As the channel quality value, interference power observed at the mobile station, common control signal reception power received by the mobile station, desired signal power to interference signal power ratio, and the like are conceivable. These channel quality values measured by the mobile station are transmitted to the base station in the process 102 of FIG.
[0034]
As shown in FIG. 3, a line quality value classification is set for each of a plurality of value ranges delimited by the threshold value. Thus, the same line quality value classification is applied to the same line quality value. The line quality value classification is selected from FIG. 3 according to the line quality value observed by the mobile station.
[0035]
In the base station, priority determination means 007 determines the priority of the combined code based on the line quality value, specifically for each line quality value classification. At that time, a priority is given to the scramble code that is the second code, or a priority is given to the first code and the second code that are the orthogonal codes, and the priority of the combined code is determined. At that time, the priority of the scramble code or the priority of the scramble code and the orthogonal code is set equal for each channel quality value classification.
[0036]
4 and 5 show setting examples of priority levels of the respective combined codes in the channel quality value classifications Q1 and Q2. 4 (a), 4 (b), 5 (a), 5 (b), the horizontal axis represents the scramble code number, the vertical axis represents the orthogonal code number, and each element of the table represents each element. This is the priority of the combined code.
[0037]
In the example of FIG. 4, priority is given to the scramble code, and the priority of the scramble code is changed according to the channel quality value. In FIG. 4A, the priority of the scramble code 1 is 1, the priority of the scramble code 2 is 2, the priority of the scramble code 1 in FIG. 4B is 2, and the priority of the scramble code 2 is 1. Is set. The higher the priority of these scramble codes, the higher the priority of the combined code.
[0038]
As a result, priorities 1 to 8 are assigned to the combined code group composed of the scramble code 1 in FIG. 4A, and priorities 9 to 16 are allocated to the combined code group composed of the scramble code 2 in FIG. Are assigned priority levels 9 to 16 to the combined code group composed of scramble code 1 in FIG. 4B, and priority 1 is allocated to the combined code group composed of scramble code 2 in FIG. ~ 8 are assigned. In this example, the orthogonal code is not given priority, and the orthogonal code is randomly assigned to each scramble code.
[0039]
In the example of FIG. 5, priority is given to the scramble code as in the example of FIG. 4, and the priority of the scramble code is changed according to the channel quality value. In FIG. 5A, the priority of scramble code 1 is 1, the priority of scramble code 2 is 2, the priority of scramble code 1 in FIG. 5B is 2, and the priority of scramble code 2 is 1. Is set. The higher the priority of these scramble codes, the higher the priority of the combined code.
[0040]
As a result, priorities 1 to 8 are assigned to the combined code group composed of the scramble code 1 in FIG. 5A, and priorities 9 to 16 are allocated to the combined code group composed of the scramble code 2 in FIG. Is assigned, and priority levels 9 to 16 are assigned to the combined code group composed of scramble code 1 in FIG. 5B, and priority level 1 is assigned to the combined code group composed of scramble code 2 in FIG. ~ 8 are assigned.
[0041]
Furthermore, in this example, priority is provided to the orthogonal code. Specifically, in FIGS. 5A and 5B, the orthogonal codes have priority 1, 2,... 8 for orthogonal codes 1, 2,. The higher the priority of these orthogonal codes, the higher the priority of the combined code.
[0042]
Specifically, the priority of the combined code group composed of the scramble code 1 in FIG. 5A is set to the combined code (1, 1) (1, 2)... (1, 8); .., 8 for the code number). Further, the priority of the combined code group composed of the scramble code 2 is set to 9, 10,..., 16 with respect to the combined code (2, 1) (2, 2). Further, the priority of the combined code group composed of the scramble code 1 in FIG. 5B is set to 9, 10,..., 16 with respect to the combined codes (1, 1) (1, 2). Yes. Further, the priority of the combined code group composed of the scramble code 2 is set to 1, 2,..., 8 with respect to the combined code (2, 1) (2, 2).
[0043]
In the examples of FIGS. 5A and 5B, the priority of the orthogonal code is uniformly determined. However, the priority may be changed according to the channel quality value as in the case of the scramble code.
[0044]
[effect]
When downlink transmission power control is applied, the transmission power directed to each mobile station varies depending on the channel quality, and the difference in transmission power does not affect the amount of interference from other downlink transmission signals received by each mobile station. Cause equality. As shown in FIGS. 4 and 5, according to the present embodiment, the priority of the combined code changes depending on the line quality value classification, and the assignment of the transmission signal and the combined code is classified according to the line quality. As a result, inequality in call reception quality at each mobile station due to a difference in channel quality is suppressed.
[0045]
In particular, when the common control signal reception power is used as the channel quality value, the following interference reduction effect can be expected.
[0046]
According to the present embodiment shown in FIG. 3, FIG. 4, and FIG. 5, the scramble is equal to the mobile stations having the same common control signal reception power, that is, the mobile stations having the same propagation loss between the base station and the mobile station. A code is assigned. Since the same orthogonal code set is assigned between transmission signals to which the same scramble code is assigned, mutual interference is suppressed to a small level.
[0047]
When transmission power control is performed, transmission signals for mobile stations with low common control signal reception power, that is, transmission signals for mobile stations with large propagation loss to the base station, are emitted from the base station with a large output. This will cause significant interference to other radio links. According to the present embodiment shown in FIGS. 3, 4, and 5, a joint code consisting of the same orthogonal code set is assigned to the transmission signal, so that mutual interference between the transmission signals is suppressed.
[0048]
On the other hand, the transmission power for compensating the propagation loss can be set small for the transmission signal directed to the mobile station having a high common control signal reception power, that is, the transmission signal directed to the mobile station having a small propagation loss to the base station. In such a transmission signal with sufficient transmission power setting, even if there is a large interference from a transmission signal directed to a mobile station with a small common control signal reception power, a high transmission power that can overcome the interference is set. It is possible to reduce interference.
[0049]
[Second priority setting example]
FIG. 6 shows a second setting example of the priority of each combined code set by the priority determination means 007 of the base station in the process 102 of FIG. 1 according to the first embodiment of the present invention. . In this example, the priority is set based on the required transmission quality. As the transmission quality requirement amount, a transmission rate, a transmission error rate, a function of the transmission rate and the transmission error rate, and the like can be considered.
[0050]
The horizontal and vertical axes in FIG. 6 represent the transmission rate and transmission error rate required by the mobile station, respectively. In FIG. 6, l-1, l-2, l-3, and l-4 are boundary lines for defining the transmission quality requirement classification Qo-a to Qo-i. These transmission quality requirements requested by the mobile station are transmitted to the base station in the process 102 of FIG. In FIG. 6, the same transmission quality requirement classification is applied to the same transmission rate and transmission error rate.
[0051]
Based on the transmission quality requirement amount requested by the mobile station, the transmission quality requirement amount classification in FIG. 6 is selected according to the transmission rate of the transmission signal and the transmission error rate required for the transmission signal.
[0052]
In the base station, the priority determination unit 007 determines the priority of the combined code based on the transmission quality requirement, specifically for each transmission quality requirement classification. At that time, a priority is given to the scramble code that is the second code, or a priority is given to the first code and the second code that are the orthogonal codes, and the priority of the combined code is determined. At this time, the priority of the scramble code or the priority of the scramble code and the orthogonal code is set equal for each transmission quality requirement classification.
[0053]
FIGS. 7 and 8 show examples of setting priorities of the combined codes in the transmission quality requirement classifications Qo-a and Qo-b. In each table shown in FIGS. 7A, 7B, 8A, and 8B, the horizontal axis represents the scramble code number, the vertical axis represents the orthogonal code number, and each element of the table represents each element. This is the priority of the combined code.
[0054]
In the transmission quality requirement classification Qo-b, it is assumed that transmission is faster than Qo-a, and the code occupation amount per call is set larger than Qo-a. As a code generation method for realizing such high-speed transmission, a method using a plurality of orthogonal codes simultaneously and a method using a hierarchical orthogonal code are known.
[0055]
In the example of FIG. 7, priority is given to the scramble code, and the priority of the scramble code is changed according to the required transmission quality. In FIG. 7A, the priority of the scramble code 1 is 1, the priority of the scramble code 2 is 2, the priority of the scramble code 1 in FIG. 7B is 2, and the priority of the scramble code 2 is 1. Is set. The higher the priority of these scramble codes, the higher the priority of the combined code.
[0056]
As a result, priorities 1 to 8 are assigned to the combined code group configured by the scramble code 1 in FIG. 7A, and priorities 9 to 8 are allocated to the combined code group configured by the scramble code 2 in FIG. 16 is assigned, priorities 5 to 8 of the combined code group composed of the scramble code 1 of FIG. 7B are allocated, and priority is assigned to the combined code group of the scramble code 2 of FIG. 7B. 1 to 4 are assigned. In this example, the orthogonal code is not given priority, and the orthogonal code is randomly assigned to each scramble code.
[0057]
In the example of FIG. 8, as in the example of FIG. 7, priority is given to the scramble code, and the priority of the scramble code is changed according to the required transmission quality. In FIG. 8A, the priority of the scramble code 1 is 1, the priority of the scramble code 2 is 2, the priority of the scramble code 1 in FIG. 8B is 2, and the priority of the scramble code 2 is 1. Is set. The higher the priority of these scramble codes, the higher the priority of the combined code.
[0058]
As a result, priorities 1 to 8 are assigned to the combined code group configured by the scramble code 1 in FIG. 8A, and priorities 9 to 8 are allocated to the combined code group configured by the scramble code 2 in FIG. 16 is assigned, priorities 5 to 8 of the combined code group composed of the scramble code 1 of FIG. 8B are allocated, and priority is assigned to the combined code group of the scramble code 2 of FIG. 1 to 4 are assigned.
[0059]
Furthermore, in this example, priority is provided to the orthogonal code. Specifically, in FIG. 8A, the orthogonal codes have priority 1, 2,... 8 for the orthogonal codes 1, 2,. In FIG. 8B, the orthogonal codes have priority 1, 2, 3, 4 for the orthogonal codes 1, 2, 3, 4, 5, 5, 6, 7, and 8, respectively.
[0060]
The higher the priority of these orthogonal codes, the higher the priority of the combined code. Specifically, the priority of the combined code group composed of the scramble code 1 in FIG. 8A is set to the combined code (1, 1) (1, 2)... (1, 8); .., 8 for the code number). Further, the priority of the combined code group composed of the scramble code 2 is set to 9, 10,..., 16 with respect to the combined code (2, 1) (2, 2).
[0061]
Further, the priority of the combined code group composed of the scramble code 1 in FIG. 8B is 5 with respect to the combined codes (1, 1 & 2), (1, 3 & 4), (1, 5 & 6), (1, 7 & 8). , 6, 7, and 8. Also, the priority of the combined code group composed of the scramble code 2 is set to 1, 2, 3 with respect to the combined codes (2, 1 & 2), (2, 3 & 4), (2, 5 & 6), (2, 7 & 8). 4.
[0062]
Here, the combined code (A, B & C) indicates that the B and C orthogonal codes are simultaneously used for the scramble code A.
[0063]
[effect]
As shown in FIGS. 6, 7, and 8, in this embodiment, the priority of the combined code is changed according to the transmission quality requirement amount classification. In this way, the assignment of the transmission signal and the combined code is classified according to the transmission speed and the transmission error rate by changing the priority of the combined code according to the transmission quality requirement amount given by the transmission speed and the transmission error rate. .
[0064]
In general, the transmission power required for a transmission signal for high-speed transmission or a transmission signal for which a low error rate is required increases. By assigning a scramble code equal to these transmission signals that can give large interference to other signals, interference between the transmission signals can be suppressed.
[0065]
On the other hand, transmission signals that can tolerate low-speed transmission or high error rates receive large interference from high-speed transmissions that are assigned different scrambling codes or transmission signals that require low error rates, but transmission that can tolerate low-speed transmission or high error rates. Since the signal requires low transmission power, large interference can be overcome by applying transmission power control. Further, by assigning a scramble code according to the transmission rate and error rate, it is possible to suppress inequality of received call quality.
[0066]
[Third priority setting example]
9, 10, and 11 show the third priority of each combined code set by the priority determination means 007 of the base station in the process 102 of FIG. 1 according to the first embodiment of the present invention. A setting example is shown. In this setting example, the priority is set based on the line quality value and the number of second codes used.
[0067]
First, the base station checks the number of combined codes used in advance for each scramble code. FIG. 9 shows an example of this. The horizontal axis represents the number of scramble codes, and the vertical axis represents the number of scramble codes used. In FIG. 9, it is assumed that the second scramble code has the highest number of uses and the fourth scramble code has the lowest number of uses.
[0068]
The base station determines the priority of the combined code based on the number of scramble codes used and the channel quality value transmitted from the mobile station. Here, as the channel quality value, the interference power observed at the mobile station, the common control signal reception power at the mobile station, and the desired signal-to-interference signal power ratio are given. To the base station.
[0069]
10 and 11 show setting examples of the priority of each combined code under the number of scramble codes used in FIG. In each table, the vertical axis represents the orthogonal code number, and the horizontal axis represents the scramble code number.
[0070]
In the example of FIG. 10, when the channel quality value transmitted from the mobile station is equal to or higher than the quality threshold value, as shown in FIG. The lower the scramble code, the higher the priority is set.
[0071]
Specifically, the priority of scrambling code 4 is 1, the priority of scrambling code 3 is 2, the priority of scrambling code 1 is 3, and the priority of scrambling code 2 is 4. The higher the priority of these scramble codes, the higher the priority of the combined code. As a result, priority 17 to 24 is configured for the combined code group composed of scramble code 1 in FIG. 10A, and priority 25 to 32 is configured to be scramble code 3 for the combined code group composed of scramble code 2. Priorities 9 to 16 are assigned to the combined code group, and priorities 1 to 8 are assigned to the combined code group composed of the scramble code 4.
[0072]
On the other hand, when the channel quality value transmitted from the mobile station is less than the quality threshold value, as shown in FIG. Set the degree higher.
[0073]
Specifically, the priority of scramble code 2 is 1, the priority of scramble code 1 is 2, the priority of scramble code 3 is 3, and the priority of scramble code 4 is 4. The higher the priority of these scramble codes, the higher the priority of the combined code. As a result, the priorities 9 to 16 are configured for the combined code group configured by the scramble code 1 in FIG. Priorities 17 to 24 are assigned to the combined code group, and priorities 25 to 32 are assigned to the combined code group composed of the scramble code 4.
[0074]
In this example, the orthogonal code is not given priority, and the orthogonal code is randomly assigned to each scramble code.
[0075]
In the example of FIG. 11, as in the example of FIG. 10, when the channel quality value transmitted from the mobile station is equal to or higher than the quality threshold value, as shown in FIG. The priority is set higher for the scrambled code having the smallest number of codes used.
[0076]
Specifically, the priority of scrambling code 4 is 1, the priority of scrambling code 3 is 2, the priority of scrambling code 1 is 3, and the priority of scrambling code 2 is 4. The higher the priority of these scramble codes, the higher the priority of the combined code. As a result, priority 17 to 24 is configured for the combined code group configured by scramble code 1 in FIG. 11A, and priority 25 to 32 is configured for scramble code 3 for the combined code group configured by scramble code 2. Priorities 9 to 16 are assigned to the combined code group, and priorities 1 to 8 are assigned to the combined code group composed of the scramble code 4.
[0077]
On the other hand, when the channel quality value transmitted from the mobile station is less than the quality threshold value, as shown in FIG. Set the degree higher.
[0078]
Specifically, the priority of scramble code 2 is 1, the priority of scramble code 1 is 2, the priority of scramble code 3 is 3, and the priority of scramble code 4 is 4. The higher the priority of these scramble codes, the higher the priority of the combined code. As a result, the priority 9 to 16 is configured for the combined code group configured by the scramble code 1 in FIG. Priorities 17 to 24 are assigned to the combined code group, and priorities 25 to 32 are assigned to the combined code group composed of the scramble code 4.
[0079]
In the example of FIG. 11, priority is also given to orthogonal codes. Specifically, the priority of the orthogonal codes is set to 1, 2,... 8 for the orthogonal codes 1, 2,. The higher the priority of these orthogonal codes, the higher the priority of the combined code.
[0080]
Specifically, the priority of the combined code group composed of the scramble code 1 in FIG. 11A is set to the combined code (1, 1) (1, 2)... (1, 8); .., 24 for the code number), and the priority of the combined code group composed of the scramble code 2 is set to the combined code (2, 1) (2, 2)... (2, 8). .., 32, and the priority of the combined code group composed of the scramble code 3 is 9, 10 with respect to the combined code (3, 1) (3, 2)... (3, 8). ,..., 16 and the priority of the combined code group composed of the scramble code 4 is 1, 2,. Yes.
[0081]
Also, the priority of the combined code group composed of the scramble code 1 in FIG. 11B is set to 9, 10,..., 16 with respect to the combined codes (1, 1) (1, 2). , Scramble code 2 is assigned a priority of 1, 2,..., 8 with respect to the combined code (2, 1) (2, 2)... (2, 8). .., 24 with respect to the combined codes (3, 1) (3, 2)... (3, 8), and the combined codes configured by the scramble code 4. The group priorities are 25, 26,..., 32 for the combined codes (4, 1), (4, 2),.
[0082]
In the examples of FIGS. 11A and 11B, the priority of the orthogonal code is uniformly determined, but the priority of the orthogonal code is changed in accordance with the number of combined codes used as in the case of the scramble code. May be.
[0083]
[effect]
Between signals to which different scramble codes are assigned, the orthogonality of the codes is not maintained, so that the amount of mutual interference is large. In particular, a transmission signal to which a scramble code with a small number of uses is assigned receives large interference from a transmission signal to which a scramble code with a large number of uses is assigned.
[0084]
When transmission power control is applied, when the channel quality value is a quality threshold value, that is, when the reception quality at the mobile station is good, the transmission power toward the mobile station can be set low. In this case, as shown in FIG. 9, FIG. 10, and FIG. 11, even when a combined code composed of a scramble code with a small number of uses is assigned to a mobile station with a high channel quality value, the transmission signal directed to the mobile station is maximum. Can withstand interference without reaching transmit power. This makes it possible to suppress interference degradation.
[0085]
Although the description has been given above using the example in which the spreading code allocation method of the present invention is applied to the base station apparatus, it can be naturally realized not in the base station apparatus but in the control station or the switching station.
[0086]
【The invention's effect】
By changing the priority of the spreading code according to the required quality and reception quality at the mobile station, inequality of call reception quality at the mobile station is suppressed, and interference is reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a base station apparatus to which a spreading code allocation method of the present invention is applied.
FIG. 2 is a flowchart of a code assignment process showing the first embodiment of the present invention.
FIG. 3 is a diagram showing an example of a relationship between a line quality value and a line quality value classification in a setting example of the first priority of joint code assignment in the first embodiment of the present invention.
FIG. 4 is a diagram showing an example of setting a first priority for combined code assignment in the first embodiment of the present invention;
FIG. 5 is a diagram showing an example of setting a first priority for combined code assignment in the first embodiment of the present invention;
FIG. 6 is a diagram showing an example of transmission quality requirement quantity classification for transmission rate and transmission error rate in a setting example of second priority of joint code allocation in the first embodiment of the present invention.
FIG. 7 is a diagram showing an example of setting a second priority for joint code allocation in the first embodiment of the present invention;
FIG. 8 is a diagram showing an example of setting a second priority for combined code assignment in the first embodiment of the present invention;
FIG. 9 is a diagram showing the number of scrambled codes used in a third priority setting example of joint code allocation in the first embodiment of the present invention.
FIG. 10 is a diagram showing an example of setting a third priority for code group assignment in the first embodiment of the present invention.
FIG. 11 is a diagram showing an example of setting a third priority for code group assignment in the first embodiment of the present invention.
FIG. 12 shows a conventional base station transmitter using single scramble code spreading.
FIG. 13 shows a conventional base station transmitter using multiple scramble code spreading.
[Explanation of symbols]
002: Multiplier
003: Modulator
004: Antenna
005: Feedback information receiving means
006: Antenna
007: Priority determining means
Si: Transmission signal for mobile station i
Co, i: orthogonal code assigned to mobile station i
spu: diffusion adder
sd: Composite spread signal
Cs: Scramble code
Sj, h: Transmission signal of mobile station h to which scramble code j is assigned
k: Number of scramble codes consumed by a certain base station
Cs, j: j-th scramble code
spu-j: Spreading and adding apparatus for spreading with scramble code j
sd-j: Composite spread signal for scramble code j
nj: number of mobile stations using scramble code j
S: Number of orthogonal codes
l-1, l-2, l-3, l-4: Boundaries defining transmission quality requirement classification
Qo-a to Qo-i: Transmission quality requirement classification
Q1, Q2, Q3: Channel quality value classification

Claims

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of coupling code with assign the second code to said first code set,
Prioritizing the combined code for each transmission signal transmitted from the base station to the mobile station based on the channel quality value of the common control signal measured by a plurality of mobile stations,
Assigning the combined code to the transmission signal based on the priority;
Spreading the transmitted signal by the assigned combined code;
A spreading code assignment method in code division multiplexing cellular, wherein the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of combined codes by assigning the second code to the first code set;
A priority is provided to the second code according to the channel quality value measured by a plurality of mobile stations ,
The higher the priority of the second code, the higher the priority of the combined code ,
Assigning the combined code to the transmission signal based on the priority;
Spreading the transmitted signal by the assigned combined code;
A spreading code assignment method in code division multiplexing cellular , wherein the spread transmission signal is transmitted to the mobile station .

A line quality value axis representing the line quality value is provided,
The line quality value axis is divided by a plurality of threshold values, and the priority of the second code is set to be equal to the line quality value in the same value range among a plurality of value ranges generated by dividing by the threshold value. The spreading code allocation method in code division multiplexing cellular according to claim 1 or 2 , characterized in that:

A priority is provided to the first code, and the priority of each combined code in a combined code group composed of the same second code is set higher as the priority of the first code is higher. Item 4. A code allocation method in code division multiple cellular according to Item 1, 2 or 3.

A line quality value axis representing the line quality value is provided,
The line quality value axis is delimited by a plurality of threshold values, and the priority of the first code is set equal to the line quality values in the same value range among a plurality of value ranges generated by dividing by the threshold value. The spreading code assigning method in the code division multiplexing cellular according to claim 4, characterized in that:

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of coupling code with assign the second code to said first code set,
Prioritize the combined code for each transmission signal transmitted from the base station to the mobile station based on a transmission quality requirement amount requested by the mobile station receiving each transmission signal,
Assigning the combined code to the transmission signal based on the priority;
A spreading code assigning method in a code division multiplexing cellular system, characterized in that the transmission signal is spread by an assigned joint code and the spread transmission signal is transmitted to the mobile station.

A priority is provided to the second code according to the transmission quality requirement amount,
The spreading code allocation method in code division multiplexing cellular according to claim 6, wherein the higher the priority of the second code, the higher the priority of the combined code.

A transmission quality requirement amount axis representing the transmission quality requirement amount is provided,
The transmission quality requirement amount axis is divided by a plurality of threshold values, and the priority of the second code is assigned to the transmission quality requirement amount in the same value range among a plurality of value ranges generated by dividing by the threshold value. 8. The spreading code allocation method in code division multiplexing cellular according to claim 7, wherein the setting is equal.

A priority is provided to the first code according to the transmission quality requirement amount,
The code division according to claim 6, 7 or 8, wherein the priority of each combined code of the combined code group composed of the same second code is increased as the priority of the first code is higher. A spreading code allocation method in multiple cellular.

A transmission quality requirement amount axis representing the transmission quality requirement amount is provided,
The transmission quality requirement amount axis is delimited by a plurality of threshold values, and the priority of the first code is assigned to the transmission quality requirement amount in the same value range among a plurality of value ranges generated by dividing by the threshold value. The spreading code assigning method in code division multiplexing cellular according to claim 9, characterized in that they are set equal.

The spreading code allocation method in code division multiplexing cellular according to claim 6, 7, 8, 9, or 10, wherein the transmission quality requirement amount is a transmission error rate.

The spreading code allocation method in code division multiplexing cellular according to claim 10, wherein the required transmission quality is a transmission rate.

The spreading code allocation method in code division multiplexing cellular according to claim 6, 7, 8, 9, or 10, wherein the required transmission quality is given as a function of transmission rate and transmission error rate.

A first code set including a plurality of first code, and a second code set including a plurality of second code, a plurality of coupling said second code with assign to the first code set Generate a sign
Investigate the number of combined codes that are composed of the same second code for each second code,
Prioritizing the combined code for each transmission signal transmitted from the base station to the mobile station based on the channel quality value of the common control signal measured by the mobile station and the number of used second codes,
Assigning the combined code to the transmission signal based on the priority;
A spreading code assigning method in a code division multiplexing cellular system, characterized in that the transmission signal is spread by an assigned joint code and the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes, and a plurality of combined codes by assigning the second code to the first code set Produces
Investigate the number of combined codes that are composed of the same second code for each second code,
When the channel quality value measured by the mobile station is equal to or higher than the quality threshold value, a higher priority is set for a combined code composed of second codes with a smaller number of used combined codes in each second code. ,
If the channel quality value is less than the quality threshold value, a higher priority is set for a combined code composed of a second code that uses a larger number of combined codes in each second code ,
Assigning the combined code to the transmission signal based on the priority;
A spreading code assigning method in a code division multiplexing cellular system, characterized in that the transmission signal is spread by an assigned joint code and the spread transmission signal is transmitted to the mobile station.

The priority is provided to the first code, and the higher the priority of the first code, the higher the priority of each of the combined codes of the combined code group composed of the same second code. The spreading code allocation method in the code division multiplexing cellular according to 14 or 15.

17. The transmission signal includes a common control signal, and the transmission signal includes a common control signal, wherein the transmission signal includes one of 9, 9, 11, 12, 13, 14, 15, or 16. Spreading code allocation method in code division multiplexing cellular.

The spreading code assigning method in the code division multiplexing cellular according to claim 17, wherein a joint code having the highest priority is assigned to the common control signal.

The spreading code allocation method in code division multiplexing cellular according to claim 1, 2, 3, 4, 5, 14, 15 or 16, wherein the channel quality value is interference signal power.

The spreading code allocation method in code division multiplexing cellular according to claim 1, 2, 3, 4, 5, 14, 15 or 16, wherein the channel quality value is received power of the common control signal.

17. The spreading code allocation method in code division multiplexing cellular according to claim 1, 2, 3, 4, 5, 14, 15 or 16, wherein the channel quality value is a desired signal to interference signal power ratio.

Check the received power of the common control signal released from the connected base station,
Check the received power of the common control signal released from the non-connected base station,
The code according to claim 21, wherein a desired signal-to-interference signal power ratio is calculated based on a ratio of received power corresponding to the connected base station and received power corresponding to the disconnected base station. A spreading code allocation method in a division multiplexing cellular.

An orthogonal code is used as the first code set, wherein the first code set is an orthogonal code, wherein the first code set is 8, 9, 10, 11, 12, 13, 14, 15, 16, The spreading code allocation method in the code division multiplexing cellular according to 17, 18, 19, 20, 21 or 22.

The gold code or a part of the gold code is used as the second code set, wherein the gold code or a part of the gold code is used. , 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23. A spreading code allocation method in code division multiplexing cellular.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of coupling code with assign the second code to said first code set,
Prioritizing the combined code for each transmission signal transmitted from the base station to the mobile station based on the channel quality value of the common control signal measured by a plurality of mobile stations,
Assigning the combined code to the transmission signal based on the priority;
A base station in a code division multiplex cellular system, characterized in that the transmission signal is spread by an assigned combination code and the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of combined codes by assigning the second code to the first code set;
Priorities are set for the second code according to channel quality values measured by a plurality of mobile stations, and the higher the priority of the second code, the higher the priority of the combined code ,
Assigning the combined code to the transmission signal based on the priority;
A base station in a code division multiplex cellular system, characterized in that the transmission signal is spread by an assigned combination code and the spread transmission signal is transmitted to the mobile station.

A line quality value axis representing the line quality value is provided, the line quality value axis is delimited by a plurality of threshold values, and a line quality value within the same value range among a plurality of value ranges generated by being delimited by the threshold value 27. The base station in the code division multiple cellular according to claim 26, wherein the priority of the second code is set equal.

The first code is prioritized according to the channel quality value, and the higher the priority of the first code, the higher the priority of each combined code in the combined code group composed of the same second code. The base station in the code division multiplexing cellular according to claim 25, 26 or 27.

A line quality value axis representing the line quality value is provided, the line quality value axis is delimited by a plurality of threshold values, and a line quality value within the same value range among a plurality of value ranges generated by being delimited by the threshold value 29. The base station in the code division multiple cellular according to claim 28, wherein the priority of the first code is set equal.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of coupling code with assign the second code to said first code set,
Prioritize the combined code for each transmission signal transmitted from the base station to the mobile station based on a transmission quality requirement amount requested by the mobile station receiving each transmission signal,
Assigning the combined code to the transmission signal based on the priority;
Spreading the transmitted signal by the assigned combined code;
A base station in a code division multiplex cellular system, wherein the spread transmission signal is transmitted to the mobile station.

31. The code division according to claim 30, wherein a priority is provided to the second code in accordance with the required transmission quality, and the higher the priority of the second code, the higher the priority of the combined code. Base station in multiple cellular.

A transmission quality requirement amount axis representing the transmission quality requirement amount is provided, the transmission quality requirement amount axis is divided by a plurality of threshold values, and transmission within the same value range among a plurality of value ranges generated by the division by the threshold values 32. The base station in the code division multiple cellular according to claim 31, wherein the priority of the second code is set equal to the quality requirement amount.

The first code is prioritized according to the transmission quality requirement, and the priority of each combined code of the combined code group composed of the same second code is higher as the priority of the first code is higher. The base station in the code division multiplexing cellular according to claim 30, 31 or 32.

A transmission quality requirement amount axis representing the transmission quality requirement amount is provided,
The transmission quality requirement amount axis is delimited by a plurality of threshold values, and the priority of the first code is assigned to the transmission quality requirement amount in the same value range among a plurality of value ranges generated by dividing by the threshold value. The base station in the code division multiple cellular according to claim 33, characterized in that they are set equal.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of coupling code with assign the second code to said first code set,
Investigate the number of combined codes that are composed of the same second code for each second code,
Prioritizing the combined code for each transmission signal transmitted from the base station to the mobile station based on the channel quality value of the common control signal measured by the mobile station and the number of used second codes,
Assigning the combined code to the transmission signal based on the priority;
Spreading the transmitted signal by the assigned combined code;
A base station in a code division multiplex cellular system, wherein the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Generating a plurality of combined codes by assigning the second code to the first code set;
Investigate the number of combined codes that are composed of the same second code for each second code,
When the channel quality value measured by the mobile station is equal to or higher than the quality threshold value, a higher priority is set for a combined code composed of second codes with a smaller number of used combined codes in each second code. ,
If the channel quality value is less than the quality threshold value, a higher priority is set for a combined code composed of a second code that uses a greater number of the combined codes in each second code ,
Assigning the combined code to the transmission signal based on the priority;
Spreading the transmitted signal by the assigned combined code;
A base station in a code division multiplex cellular system, wherein the spread transmission signal is transmitted to the mobile station.

The priority is provided to the first code, and the higher the priority of the first code, the higher the priority of each of the combined codes of the combined code group composed of the same second code. A base station in the code division multiple cellular according to 35 or 36.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Assigning the second code to the first code set, generating a set of the first code and the assigned second code;
Priorities are assigned to the set of the first code and the assigned second code for each transmission signal transmitted from the base station to the mobile station based on the channel quality value of the common control signal measured by a plurality of mobile stations. ,
Assigning the set of the first code and the assigned second code to the transmission signal based on the priority;
Spreading the transmission signal by a set of the first code and the assigned second code;
A spreading code assignment method in code division multiplexing cellular, wherein the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Assigning the second code to the first code set, generating a set of the first code and the assigned second code;
A priority is provided to the second code according to the channel quality value measured by a plurality of mobile stations ,
The higher the priority of the second code, the higher the priority of the set of the first code and the assigned second code ,
Assigning the set of the first code and the assigned second code to the transmission signal based on the priority;
Spreading the transmission signal by a set of the first code and the assigned second code;
A spreading code assignment method in code division multiplexing cellular , wherein the spread transmission signal is transmitted to the mobile station .

A first code set including a plurality of first codes;
A second code set comprising a plurality of second codes,
Assigning the second code to the first code set, generating a set of the first code and the assigned second code;
Prioritize the set of the first code and the assigned second code for each transmission signal transmitted from the base station to the mobile station based on the transmission quality requirement amount requested by the mobile station receiving each transmission signal,
A set of the first code and the assigned second code is assigned to the transmission signal based on the priority, and the transmission signal is spread and spread by the set of the first code and the assigned second code. A spreading code allocation method in code division multiplexing cellular, wherein the transmission signal is transmitted to the mobile station.

The second code is prioritized according to the required transmission quality, and the higher the priority of the second code, the higher the priority of the set of the first code and the assigned second code. The spreading code allocation method in the code division multiplexing cellular according to claim 40.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Assigning the second code to the first code set, generating a set of the first code and the assigned second code, and based on a line quality value of a common control signal measured by a plurality of mobile stations A priority is assigned to the set of the first code and the assigned second code for each transmission signal transmitted from the base station to the mobile station, and the first code and the assigned are assigned to the transmission signal based on the priority. Assign a second set of codes,
Spreading the transmission signal by a set of the first code and the assigned second code;
A base station in a code division multiplex cellular system, wherein the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes and a second code set including a plurality of second codes;
Assigning the second code to the first code set, generating a set of the first code and the assigned second code, and generating the second code according to channel quality values measured by a plurality of mobile stations Priorities,
The higher the priority of the second code, the higher the priority of the set of the first code and the assigned second code, and the second code assigned to the transmission signal based on the priority. Assign a set of codes,
Spreading the transmission signal by a set of the first code and the assigned second code;
A base station in a code division multiplex cellular system, wherein the spread transmission signal is transmitted to the mobile station.

A first code set including a plurality of first codes;
A second code set including a plurality of second codes, assigning the second code to the first code set, and generating a set of the first code and the assigned second code,
Prioritize the set of the first code and the assigned second code for each transmission signal transmitted from the base station to the mobile station based on the transmission quality requirement amount requested by the mobile station receiving each transmission signal,
Assigning the set of the first code and the assigned second code to the transmission signal based on the priority;
A base station in a code division multiplex cellular system, wherein the transmission signal is spread by a set of the first code and the assigned second code, and the spread transmission signal is transmitted to the mobile station.

A priority is provided to the second code according to the transmission quality requirement amount,
45. The base station in the code division multiple cellular system according to claim 44, wherein the higher the priority of the second code, the higher the priority of the set of the first code and the assigned second code.